Patent Document 1 discloses a technology for realizing optimum color mixing ratios and high luminance by combining green light from two different directions of a cross-dichroic prism and further combining the green light with red light and blue light. In other words, a high-luminance image display device is realized by using three liquid crystal panels of red, green and blue and causing a blue LED and green LED to simultaneously emit light and irradiate the same liquid crystal panel for blue.
Patent Document 2 discloses a technology for combining the output light from a plurality of light-emitting elements that emit light of different colors, then detecting, for each color, a portion of the combined light by using color filters that correspond to each light color, and then using these values to control the output of the light source.